The testing of electrical equipment requires the use of reference signals (in some cases, the reference signals are provided by the equipment being tested) and determining the response of the equipment to the reference signals. The present invention is a versatile source of such reference signals in that it generates said signals in a variety of waveforms over a relatively wide range of frequencies and with a relatively high resolution. Additionally, the reference signal are generated as amplitude modulated signals with either full carrier or suppressed carrier characteristics as is advantageous for the intended purposes. In order to achieve maximum flexibility and a choice of signal waveforms, frequencies and amplitudes, the reference signal generator of the invention is arranged to communicate with a main central processing unit via a multibus interface. High resolution of the reference signal output is achieved through an arrangement of multiplying digital to analog converters and operational amplifiers. The reference signal generator of the invention as described accomplishes its purpose in a single, compact arrangement and provides a capability that would otherwise only be available by providing many separate signal sources.
Accordingly, it is an object of the present invention to avoid a multiplicity of separate reference signal sources by providing in a single compact arrangement a versatile reference signal generator for generating output reference signals of the type used for testing electrical equipment.